Cable safety clamping device for oil wells and the like



Sept. 16, 1969 w. L. CURTIS ET AL 3,457,224

CABLE SAFETY CLAMPING DEVICE FOR OIL WELLS AND THE LIKE Filed May 5,1968 2 Sheets-Sheet 1 ma; 36 P INVENTORS ATTORNEY Sept. 16, 1969 w, L,cuR s ET AL 3,467,224

CABLE SAFETY CLAMPING DEVICE FOR OIL WELLS AND THE LIKE Filed May 5.1968 2 Sheets-Sheet 2 WILLIAM L CURTIS BY BLLLY D CURTIS 7 ,7 3. 6' AATTORNEY United States Patent 3,467,224 CABLE SAFETY CLAMPING DEVICE FOROIL WELLS AND THE LIKE William L. Curtis, Van, Tex., and Billy DeanCurtis, Alexandria, Va., assiguors of fifty-one percent to Mary LouCurtis, North Plaiufield, N.J., and forty-nine percent to ContractorsServices, Inc., Alexandria, Va.

Filed Mar. 5, 1968, Ser. No. 710,602 Int. Cl. B65h 59/16; A62b 1/20;F16g 11/00 US. Cl. 18865.1 Claims ABSTRACT OF THE DISCLOSURE A cable orline safety clamping mechanism for use in snubbing and retainingparticularly broken cables which often result from use in oil welloperations. The safety clamp mechanism herein comprises a clamp housingembodying therewithin a pair of gripping wedges or slips at least one ofwhich may be of the servo actuated type, disposed oppositely about acable, said slips being fluid pressure operated responsive to usually anoverhead break in a cable which is threaded over one or more sheavessupported in the wells superstructure, and said slips being instantlyactivated to snub and grip the cable to preclude it being lost downinside of the well. One preferred form embodies electrical switch meansto automatically activate the safety clamping slips by fluid pressuremeans responsive to the whipping action of a slack cable after itbreaks, while another embodiment provides for manual energization of theswitch means by one of the attendant workers, responsive to observing abroken cable.

Statement of invention The present invention relates to an improvedsafety retention clamping means usable in connection with a heavy loadlifting cable, rope and similar lines. More specifically it may relateto a safety device for clamping and holding in a given position aso-called catline or other cables as often used in association withportable rigs now commonly utilized in oil field work.

As a matter of background, it is common practice in oil field operationsto utilize all steel portable drilling rigs and to employ variousmakeshift holding devices and means to attempt to snub the catline withthe so-called cathead or to otherwise grip and retain a cable for agiven reason. It is a hazardous task to the workmen because the cablesbecome frictionally burnt, chafed and sometimes break causing injury tothose workmen within the vicinity of the falling load or whipping brokencable ends.

While we are aware of various prior art devices intended for use inholding and clamping such lines, there seems to be the need for animproved device having increased eifectiveness and one which is moreautomatically responsive to a cable break for instantaneous operation.

Objects Accordingly, it is a principal object of the present inventionto provide for a novelly improved cable clamping device having a twopart housing embodying a pair of Wedge shaped gripping slip membershaving serrated gripping teeth disposed oppositely about a cable passingthrough a central cable aperture. The slip members are fluid-pressureoperated responsive to electrical solenoid- '5 operated switch meansactivated automatically by the whipping action of a broken or slakenedcable, with the slips tapering to their Wedge shapes in the direction oftravel which the broken cable would normally follow.

Another primary object is to provide for an improved cable clampingdevice of the character described of which one of the dual slip membersis positively activated by 3,467,224 Patented Sept. 16, 1969 ICC fluidpressure means to efi'ect engagement of said one slip with the runningcable, whereupon continued application of the fluid pressure forces aslight and nearly instantaneous lateral displacement of said cablewhereby it frictionally engages the other of said slip members with theresult that the second slip wedge becomes servoactuated and is drawn,together with the first slip, into continuously tightening engagementwith the cable and the clamp housing to effectively brake the cable.

A further object of the present invention is to provide an improvedcable clamp of the aforedescribed character embodying double actingswitch means in combination with fluid pressure means to reset thedevice once a cable has been repaired, and which may be manually orautomatically operated.

These and other objects including the provision of an improvedmost-effective clamping device which may be produced at relativelycompetitive costs, will become more readily apparent from the followingdetailed description taken in conjunction with the illustrative drawingswhere- Figure description FIG. 1 is representative of an elevationalview of a field rig structure embodying the improved inventiontherewith;

FIG. 2 is an enlarged detail view, partially in elevation and partiallyin cross-section, depicting one embodiment of our improved cableclamping device;

FIG. 3 is an enlarged elevational view, similar to FIG. 2, depicting asecond embodiment of our improved device, with the operating membersshown in dotted outline;

FIG. 4 is a top plan view generally representative of our improveddevices but particularly of that embodiment depicted in FIG. 3;

FIG. 5 is a bottom plan view of the cable clamping devices shown inFIGS. 2 and 3;

FIG. 6 is an enlarged perspective detail view of one of the slip membersadapted to frictionally engage and clamp the cable with which thepresent invention is associated; and

FIG. 7 is a fragmentary elevational view similar to the structuredepicted in FIG. 1 but showing a modification operative automaticallyresponsive to a broken cable.

Present invention Referring now to the general arrangement depicted inFIG. 1, wherein like reference characters designate corresponding partsin this and the other drawing figures, 10 designates generally theportable steel rig with which the improved clamping means of thisinvention is associated. The conventional so-called Christmas treeextending approximately 2%. feet up out of the well is designatedgenerally at 12 and may comprise an 8" diameter pipe 14 terminatingabout one foot above the ground, and a smaller 3" diameter well pipe 16projecting coaxially up within the pipe 14 and terminating approximatelytwo to two and one-half feet above the ground in a T or X fitting 18, asshown. One side of the horizontal arm of the fitting 18 is plugged offas at 20, while the opposite side is provided with a pipe line 22 whichleads to one or more underground storage facilities, not shown. Out ofthe top of the fitting 18, there projects a short length of pipe towhich is attached a conventional gate valve 24, and thereabove is anextended 20 foot to 30 foot length of pipe 26 having a threaded collar28 aflixed on the end thereof. Said upright piping 26 is steadied by andsecured in the usual manner (not shown) to the rigging 10.

Our improved cable clamping assembly is designated generally 30 and ispreferably threadedly mounted atop the length of pipe 26 by means ofsaid collar 28. Also threadedly mounted atop the cable clamping assembly30 is a conventional stufling box 32 to effect cleaning of the cable,with the cable 34 extending from the workpiece within the well upthrough the pipes 16 and 26, passing centrally up through the clampingdevice 30 and stufiing box 32 and then threaded around a sheave 36 whichis suspended perhaps another thirty feet or so overhead in the rigging.Said cable 34 is then directed downwardly and is connected in the usualmanner with the usual rotary winding and lifting winch mechanismgenerally designated 38 disposed on a suitable tractor generator 40 atground level approximately twenty feet or so away from the base of therigging.

Referring now more specifically to the constructional and operationaldetails of our improved clamping devices, as depicted in FIGURES 2, and6, it will be noted that the assembly 30 comprises basically a two-partgenerally cylindrical housing including an upper housing member 42 and alower housing member 44, both having complementally formed and aperturedannular joining flanges 46 and 48 respectively, preferably an interposedsealing gasket 47, and being fastened together by a plurality of boltassemblies 50.

Upper housing 42 is of a slightly elongated cylindrical form and isprovided with a central bore 52 of a diameter slightly in excess of andadapted to receive passage therethrough of the cable 34. Flange 46 ispreferably integrally formed with the housing body 42 at one end, asshown, and is provided at the opposite end with an enlarged femalethreaded recess 54, within which the aforementioned conventionalstuffing box 32 is threadedly mounted. An annular boss 56 having atapered shoulder 58 projects slightly beyond the face of the mountingflange 46, and is of a diameter generally corresponding to that of thecylindrical body 42. A pair of axially extended piston cylinders 60 aresuitably provided within said housing on diametrically opposite sides ofthe central cable bore 52, having their open ends communicating with theflanged end of the housing and their closed ends terminating inwardlyadjacent the aforementioned threaded recess 54 thereof. This halfhousing is further provided with fluid inlet-outlet ports 62, 62communicating with the respective cylinders 60, 60. Each of thecylinders is fitted with an operating piston 64 having the usual sealingrings 65. The pistons are provided with flat upper surface 66 againstwhich fluid pressure is exerted during operation, and are each furtherprovided with a substantial conical recess 68 having a rounded seatadapted to receive the rounded end of a piston-operated toggle-arm 70for a purpose to become apparent shortly hereafter.

The lower housing member 44 is also provided with a central bore 72corresponding in diameter and in coaxial alignment with bore 52. Theflanged end 48 is provided with a recess 74 of complementaryconfiguration tothat of boss 56. Also extending generally axially intothe lower body member from this flanged end are a pair of preferablygenerally cylindrical shaped bores 76, 76 disposed on diametricallyopposite sides of the central cable-receiving bore 72. Bores 76, 76 aredisposed so that their upper open ends are in alignment with therespective cylinder bores 60, 60 of the upper housing half member whenthey are in assembled condition. Bores 76, 76 are further provided withcoaxial counter bores 78, 78, with the common axis thereof beingsubstantially inclined toward the axis of said central cable bore 72,perhaps having an included angle with a vertical axis of approximately20. The bores 76, 78 per se do not intersect with the central cable bore72, although there is provided a milled or otherwise suitably formedslotway 80 interconnecting the bores 76, 76 and the bore 72. FIGS. 2 and5 better show the slotway 80 which is of less thickness than thediameter of the bores 76, and generally corresponds in thickness to thediameter of the cable bore 72.

A pair of generally wedge-shaped cable-gripping members hereinafterdesignated slip members 82, 82 are .4 adapted to be slidably disposedwithin slipways constituted by a combination of the respective bores 76,78 and slotway 80, and said slips will now be described in more detail.Each slip member 82 (see FIGS. 2 and 6) comprises a generallycylindrical first body portion 84 having a diameter complemental to thatof bore 76 and preferably an integrally formed depending second bodyportion 86 of reduced diameter complemental to that of counter bore 78.A web or key 88 of a thickness to complementally slide within theslotway is preefrably integrally formed with and extends the length ofslip portion 84 and terminates in a serrated edge 90, said edge 90 beingadapted to engage the cable 34 responsive to actuation of thefluid-pressure-operated piston 64 and toggle arm 70. The upper end orface 90 of the slip is provided with a rounded recess 92 tocomplementally receive the other rounded end of toggle arm 70 describedhereinabove.

At the lowermost end of each counterbOre 78 there is another fluidinlet-outlet port 94 of smaller diameter than port 62 in the upper halfhousing, the purpose of which will become more apparent in the followingoperational description. The lowermost end of depending slip portion 86is provided with one or more suitable annular fluid sealing rings 96.

An electrically operated solenoid valve assembly designated generally at98 is mounted to the lower clamp housing portion 44 in any suitablemanner, not shown. The valve assembly 98 is of a conventionalconstruction which embodies a double acting piston or valve, which whenin one given position opens the passageway which connects fluid conduits100, 102 and closes off the internal communication between conduit 100and 104. When said valve is in the other given position it blockscommunication between conduits 100 and 102 while establishingcommunication between conduits 100 and 104, the purpose of which will befurther clarified hereinafter. The solenoid valve is connected to asuitable source of electrical power as at the tractor-generator 40 bymeans of electrical conduit designated 106. A manually operable switch105 may be disposed on the winch brake lever 107 of the tractor 40.

A source of fluid operating pressure, such as a tank of compressed airdesignated 108, is mounted near the upper end of pipe 26 and beneath thecable clamping device 30, as better seen in FIG. 1. Because the tank 108may contain air under as much pressure as 1,000 lbs., a suitablepressure regulator 110 is mounted atop the tank to effect a reduction ofthe pressure to a more suitable predetermined operating pressure, suchas approximately lbs. per sq. inch. Conduit 100 is interconnected bysuitable fittings between the pressure regulator valve 110 on tank 108and the solenoid valve 98. Conduit 102, leading upward from the solenoidvalve 98, divides via a Y fitting 112 and the respective dividedbranches thereof are attached to the respective inlet-outlet ports 62,62 of the upper housing by means of suitable threaded fittings 114 orthe like. Conduit'104 leading away from the valve 98 also divides, inthe preferred form depicted in FIG. 2, via a Y fitting 116, with therespective divided branches being similarly attached to the inlet-outletports 94, 94 of the lower housing by means of suitable threaded fittings118. Lowermost housing 44 is provided preferably with a male threadedlowermost portion 119 to be accomplementally received for mounting theassembly 30 in said collar 28.

Operation Although the operation is now generally apparent from theforegoing detailed description, a review of the full operation of ourimproved cable clamping devices will be undertaken. Should an emergencyor any other condition arise, during the well operations, whereby it isdesirable or becomes mandatory that the cable 34 be elfectively clampedor locked in a predetermined condition, our improved clamping devicebecomes operational by the mere closing of switch 105 at the tractor byone of the attendant workmen. The closing of switch 105 instantlyactivates the solenoid switch 98, opens the passageway through the valvebetween fluid pressure conduits 100 and 102 whereby the fluid pressureenters the upper housing via ports 62, 62 to exert a downwardly drivingforce on the pistons 64, 64, and in turn via the toggle arms 70, 70activates the wedge-shaped slip members 82, 82. It is apparent that suchaction forces the slips downwardly and angularly toward the cable, withthe serrated gripping edges 90, 90 effectively interengaging the cable34 to lock same in an immovable condition.

It is further apparent that in the case of a broken cable havingoccurred at a point above the clamping device, then the weight of thetool or work member suspended by said cable would cause the cable to bedrawn downwardly, in the direction of the arrow 120, into the well.Thusly, with the cable traveling in said direction and the slips havingbeen activated as aforedescribed, it is further apparent that the slipsare further characterized by a positive servo action, due to thecam-like action imparted to the slips responsive to their respectivedownward travel in the inclined slipways 76, 78, effected by the pull ofthe cable, Accordingly, a more positive and improved cable lockingdevice has been evolved which is instantly and easily activated, andonce the emergency or other condition which triggered the operation ofour device has been remedied, our cable clamp is readily deactivated aswill be described in the following.

De-activation of clamping device With the embodiment of a double actingsolenoid valve, when the aforementioned condition has been remedied andreverse direction tension is applied to the cable, it is only necessaryto open switch 105 which by means of the double-acting solenoid valve inturn closes off communication between fluid pressure conduits 100 and102, and simultaneously establishes communication of the fluid pressurein conduit 100 with that in conduit 104. This, in turn, directs fluidpressure into the lower housing ports 94, 94 against the respective endsof the lower portions 86 of the slip members 82, 82, thereby raising theslips and disengaging them from their locked condition with the cable.It is further apparent that this action forces both the slips 82, 82 andtheir respective operating pistons 64, 64 back up into their cockedposition where they are ready again to meet any emergency condition.

Modified embodiments Referring to the modified embodiments depicted inFIGS. 3 and 4, it will be observed that the same basic construction isutilized, with similar but primed reference characters designatingcorresponding parts of both embodiments. The only differencestructurewise is that only one operating piston and piston cylinder areutilized instead of two of them. The operation is generally the sameexcept that only one of the slip 82 initially is activated by the fluidpressure operation of the corresponding piston 64. Upon continuingapplication of the fluid pressure exerting its downward force on slip82', the gripping serrations of the slip engage the cable, and itscontinuing downwardly and angularly directed motion forces the cablelaterally until the normally small clearance tolerance between it andthe slips is overcome. It is then apparent that the serrated portion ofthe other slip 82" as frictionally engaged by the downward motion of thecable, serves to draw said other slip 82" downwardly whereby its cammingaction with slipway 76', 78' serves to drive it into an ever tightening,servo-actuated locking condition, together with the first slip 82' toeffectively lock the cable in the desired condition. Release andresetting of this embodiment of our improved cable clamp is achieved inthe same manner as that of the first-described embodiment.

Proceeding now to FIG. 7, there is fragmentarily shown the upper portionof the same rigging 10, with our improved cable clamp assembly 30 beingmounted in conjunction with means to enable it to become automaticallyoperable responsive to an overhead break in the cable, therebyprecluding the necessity of relying upon the human reaction to activatesame, which human reaction may be more susceptible to error and abelated application of the clamping device.

Therefore, a second switch means is disposed above the clamping device30, with the cable 34 passing up through an aperture provided in saidswitch means 130. With cable under its normal operating tension, thereis suflicient clearance whereby the switch thereof is maintained in itsopen condition. Suitable electrical control wiring is schematicallyshown as at 132 connecting the switch means 130 with the previouslydescribed solenoid switch means 98, which together with either of theaforementioned clamping assemblies 30 or 30' remain the same.

Automatic operation is achieved when an emergency condition comes intoexistence as by the breaking of said cable at a position above theclamping assembly. Due to the whipping action of a slackened or brokencable, as depicted by broken line 134 in FIG. 7, switch of switch means130 will be closed thereby nearly instantaneously energizing solenoidswitch 98 which results in the identical application of the cableclamping action as already described hereinabove.

From the foregoing detailed description and operation, it is apparentthat we have evolved a greatly improved cable clamping device whichachieves the objects and advantages as set forth in the preamble andforegoing specification of this application.

While specific embodiments and details related thereto have been shownand described, it will be obvious to those skilled in the art thatvarious changes and modifications may be made therein without departingfrom the inventive scope.

We claim:

1. A cable clamping device of the class described com prising:

(a) an elongated housing body including lower and upper portions andhaving an axially aligned cablereceiving aperture extendingtherethrough;

(b) said housing body having at least one slipway inclined with respectto the axis of the body, said slipway disposed in the lower portion andincluding an inclined wall facing the cable-receiving aperture;

(0) said slipway further including a vertically disposed slotwayinterconnecting the inclined wall and the cable aperture;

(d) slip means including at least one generally wedgeshaped slip membermounted for slidable movement within said slipway and upon the inclinedwall;

(e) said slip means further including cable-engaging means projectibleinto and out of said cable aperture for selective engagement of thecable with which the device is to be associated; and

(f) actuating means including fluid pressure means operatively connectedwith said slip means to urge the latter into and out of engagement withsaid cable.

2. A cable clamping device as defined in claim 1 wherein the fluidpressure actuating means includes piston means disposed in the upperportion of the body housing, and operably connected with the slip meansaforesaid.

3. A cable clamping device as defined in claim 1 wherein the housingbody comprises generally cylindrically formed upper and lower bodyportions having complemental joining flange means, and includingmounting means at the opposite ends of said body.

4. A cable clamping device as defined in claim 1 wherein the housingbody comprises generally cylindrically formed upper and lower bodyportions having complemental joining flange means, said upper bodyportion including reciprocable piston means operatively connected withthe slip means to efiect movement of the latter into engagement withsaid cable.

5. A cable clamping device as defined in claim 1 wherein the housingbody is provided in the upper portion with piston means in operativecommunication with the slip means to efiect movement of the latter intoengagement with said cable.

6. A cable clamping device as defined in claim 1 wherein the upperhousing portion is provided with dual piston means disposed on oppositesides of the cable aperture, and the lower portion is providedwith dualslipways each inclined to the axis of the body, slip means includingdual slip members slidable in the dual slipways and the latter beingdisposed oppositely of the cable aperture and in corresponding alignmentwith the piston means.

7. A cable clamping device as defined in claim 1 wherein the fluidpressure means includes:

(a) piston means disposed in the upper portion of the housing body, a(b) a supply of pressurized operating fluid connecte with the housing ata point above and in communication with said piston means and alsotherewith below and in communication with said slip means, and v (c)valve means interposed between said piston means and said slip means forselectively directing a pressurized fluid to the piston means forefiecting clamping engagement of the slip means with the cable andsubsequently beneath the slipmeans to effect disengagement thereof.

8. A cable clamping device as defined in claim 1,

wherein the actuating means includes electrically energized valve meansto eifect operation of the fluid pressure actuating means.

9. The device as defined in claim 7 wherein the valve means includes anelectrically solenoid-operated valve.

10. The cable clamping device as defined in claim 7 wherein theactuating means is automatically operative responsive to a break in thecable; and said actuating means includes a first electrical switch meansconnected with a suitable source of electrical energy; said first switchmeans being fixedly mountable above the clamping device and includingmeans having a passageway through which the cable passes in a manner anot to engage or close the contacts of said first switch when the cableis under normal operating tension, but which will close responsive tocontact by a slackened or broken cable; a second electrical switch meanswith which the first switch means is operatively connected, and saidsecond switch means being operatively connected with said valve means asinterposed between the piston means and slip means aforesaid.

11. A cable clamping device comprising an elongated housing bodyincluding upper and lower portions and 8 having an axially extendedcable-receiving aperture extending therethrough, means for securing thebody on the framework of an oil well rig with which it is adapted to beassociated and in a manner to receive an operating cable through saidaperture, a plurality of cable-clamping slips slidably mounted in thelower body portion to be selectively moved into and out of engagementwith said cable," said slips being generally wedge-shaped and havingcomplementally formed slip ways formed in the body including inclinedwalls facing and in open communication with the cable aperture, fluidpressure operated piston means including at least one pistonreciprocably mounted within a piston cylinder provided in the upper bodyportion, said piston being operatively connected with said slip means, asource of pressurized fluid operatively connectable with said clampingdevice, and actuating means incltiding selective valve means interposedbetween the source of pressurized fluid to effect operation of the slipmeans to selectively project the same into and out of clampingengagement with said cable.

12. The cable clamping device as defined in claim 11 wherein theactuating means is automatically set into operation responsive towhipping action of a broken cable and includes electrical switch meanswhich are actuated by engagement therewith of a slackened or brokencable, said switch means being operatively connected to the valve meansaforesaid.

13. The cable clamping device as defined in claim 11 and includingmanually and automatically operable electrical switch means foractuating said clamp.

14. The cable clamping device as defined in claim 11 wherein theactuating means includes an electrical circuit, a source of electricalpower and an electrical solenoid mechanism connected with said valvemeans to effect selective operation of the valve, and also includes amanual switch means in the electrical circuit adapted to be operated byan attendant workman.

15. The cable clamping device as defined in claim 11 wherein the valvemeans is an electrically operated solenoid valve mechanism mounted onthe clamp body.

References Cited UNITED STATES PATENTS 2,991,526 7/1961 Kuebler 18865.13,049,775 8/ 1962 Ondeck 24-126 3,335,469 8/ 1967 Shand et al 18865.1

MILTON BUCHLER, Primary Examiner THOMAS W. BUCKMAN, Assistant ExaminerU.S. Cl. X.R. 24-126; 182191

